The invention relates to microelectromechanical system (MEMS) processes, and more particularly, to microelectromechanical optical (MEMO) display device processes.
A wide variety of optical devices may currently be fabricated using micromachining and microelectronic fabrication techniques.
In some cases, for example, MEMS devices may comprise optical components, specifically referred to as MEMO display devices. One example of a MEMO display device is the interference modulator described in U.S. Pat. No. 5,835,255, which may be fabricated in an array and used in a reflective display wherein each interference modulator serves as a pixel to provide a desired optical response.
FIG. 1 shows a side view of a conventional interference modulator in two states. Referring to FIG. 1, numeral 102 denotes a pixel in an undriven state and numeral 104 denotes a pixel in a driven state. In the driven state, a mirror plate 110 is in direct contact with a substrate 120 such that the interference modulator absorbs incident light and appears black to a viewer 140 through the substrate 120. In the undriven state, an air gap 112 exists between the mirror plate 110 and the substrate 120 such that the interference modulator appears to be a bright color (for example, blue). Additionally, numeral 130 denotes a post for supporting the mirror plate 110.
U.S. Patent Application Publication No. 2002/0015215 to Miles, the entirety of which is hereby incorporated by reference, discloses a method for forming an interference modulator, comprising patterning an aluminum layer to form a mirror plate.
U.S. Patent Application Publication No. 2003/0152872 to Miles, the entirety of which is hereby incorporated by reference, discloses a method for forming an interference modulator, comprising forming a stack layer on a substrate and exposing a photosensitive layer deposited thereon using the stack layer as a photomask.
U.S. Patent Application Publication No. 2003/0027636 to Miles, the entirety of which is hereby incorporated by reference, discloses a method for forming an interference modulator, comprising forming a light-absorbing layer on a portion of a substrate.